1. Field of the Invention
The present invention relates to a planar light source device and a liquid crystal display device assembly.
2. Description of the Related Art
With liquid crystal display devices, the liquid crystal material itself does not emit light. Accordingly, a planar light source device (backlight) is placed at the rear face of and immediately under a display region configured of multiple pixels, so as to illuminate the display region of the liquid crystal display device, for example. Note that with a color liquid crystal display device, one pixel is configured of the three sub-pixels of a red light-emitting sub-pixel, a green light-emitting sub-pixel, and a blue light-emitting sub-pixel, for example. An image is displayed by causing liquid crystal cells making up each sub-pixel to serve as a type of light shutter (light valve), i.e., by controlling the light transmissivity (aperture ratio) of each sub-pixel to control the light transmissivity of the illumination light (e.g., white light) emitted from the planar light source device.
With related art, a planar light source device in a liquid crystal display device assembly illuminates the entire display region with a uniform and constant brightness, but a configuration different from such a planar light source device, i.e., a planar light source device of a configuration which is configured of multiple light-emitting device units in which the illumination distribution of multiple display region units is changed (a partial driving type or a division-driving type planar light source device) is described in Japanese Unexamined Patent Application Publication No. 2005-258403. Such control of the planar light source device (also called partial driving or division driving of the planar light source device) is used to increase contrast ratio due to increase in the white level and reduction in the black level at the liquid crystal display device, whereby image display quality can be improved, and power consumption of the planar light source device can be reduced.
The light source making up each planar light source unit in the planar light source device is often configured of red light-emitting diodes, green light-emitting diodes, and blue light-emitting diodes, with white light being obtained by color mixing of the red light, green light, and blue light obtained by emitting light from these light-emitting diodes, and illuminating the display region of the liquid crystal display device with this white light.